JP2004126844A - Server computer device with cache memory control function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a server computer with a cache memory control function whereby control for refreshing a cache memory area can be efficiently carried out. <P>SOLUTION: The server computer device includes an inquiry request answering means 21 for answering an inquiry request coming from a user's terminal; a database updating means 22 for updating and recording a database with received real-time information and recording this update in a database update event table 32; a cache memory area 25 enabling direct reading and/or writing at high speeds; a cache managing means 23 for monitoring the updates of the database 31 and directing deletion of response data corresponding to the contents of a cache memory; and a cache control means 24 for registering and/or deleting the cache memory. Response data information synchronized with the contents of the database is recorded in the cache memory area at all times. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cache technology for providing a cache memory, which is a recording medium that can be accessed at a higher speed, between a disk device and a computer device in order to improve computer response and reduce server load. .
[0002]
[Prior art]
Due to the difference between the processing speed of the CPU and the access speed of the disk device in which the database is stored, the waiting time from when the CPU issues a read / write command to the disk device until execution is increased. In order to alleviate the problem of the difference, a cache technique of providing a cache memory (JP-A-11-149405, JP-A-2000-242533, JP-A-2000-29765, etc.) has been proposed.
[0003]
Such a cache technology is also applied to the inquiry response field of the Internet to improve the response and reduce the server load. That is, a Web page image (so-called static content) by an HTML tag in a server computer on the Web, or a response (so-called dynamic content) by a CGI (Common Gateway Interface) program executed by the server computer in response to a request from a Web browser. Was cached on a medium that can be accessed at higher speed, so that it was used for high-speed response and reduction of server load.
[0004]
Normally, a memory that can be accessed at high speed is used for the location to be cached. However, when the contents of the database configured by the disk device from which the data is read are changed, the refresh of the cache memory is performed in advance. The contents of the read source database are compared with the contents of the cache memory at each elapsed caching time interval or each time a user requests.
[0005]
This comparison is a method of checking the time stamp attached to the data in the cache memory and the update time stamp of the corresponding data in the database device. However, the disk access must be performed every time an inquiry response is sent via the Internet. Therefore, there is a problem that the cache effect is reduced by half. In particular, the smaller the content, the less the cache effect, which is disadvantageous when used in the inquiry response field on the Internet.
[0006]
When the contents of the database of the disk device from which the data is read are response data processed by the above-described CGI program, a logic for refreshing the cache with the elapsed time (valid period) is used. Since the actual original data is not always changed exactly at the elapsed time interval, there is a problem that unnecessary refresh of the cache memory occurs.
[0007]
Further, there has been a problem that even if the content from which data is read is changed by a program, old information in the cache memory for a certain period of time, that is, old information with low accuracy is responded.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problem, and an object thereof is to register cache data in a cache memory area only when response data corresponding to an inquiry request is not registered in the cache area. When the contents of the database of the disk device from which the data is read are changed, the corresponding response data in the cache area is deleted in real time, so that the response data constantly searched and read from the cache area is synchronized with the database. The present invention provides a server computer with a cache memory control function in which only the response data information is recorded in the cache area, and only the response data information with high inquiry frequency is recorded in the cache area.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a server computer device with a cache memory control function of the present invention includes a database that is updated in real time as needed, receives an inquiry request from a user terminal via the Internet, and A server computer device for returning response information obtained by searching and processing request contents selected by a user,
The server computer device includes a Web server that receives an inquiry request from a user, a database server that records real-time information received from a real-time information providing system via a communication control device, and an information inquiry request from a user terminal. And an application server that responds by searching, reading and processing the database of the database server, and transmitting the processed data via the Web server.
The database server includes at least a database update event table that records update information of database contents in addition to the inquiry response database, and a cache correspondence information table that records correspondence information between database contents and cache memory contents.
The application server includes: an inquiry request response unit that responds to an inquiry request from a user terminal; a database updating unit that updates and records a database with the received real-time information and records the database in a database update event table; A high-speed, directly readable / writable cache memory area for recording created response data, a cache management means for monitoring the update of the database and instructing deletion of the corresponding response data in the cache memory contents, and registration of the cache memory A cache control means for performing deletion, and response data information synchronized with the contents of the database is always recorded in the cache memory area.
[0010]
According to the present invention, the occurrence of a database update event is constantly monitored by the cache management means, and the contents of the cache area to be refreshed are deleted by the cache control means. Can be registered and refreshed. Therefore, response data in which synchronization of the cache area is guaranteed can be obtained. Further, it is possible to eliminate the disk access operation for the synchronization check using the time stamp of the cache memory and the database.
[0011]
The inquiry request responding means, upon receiving an inquiry request from a user, first searches whether the corresponding response data is recorded in the cache memory area, and if not, searches the inquiry response database to retrieve the response data. Is generated and transmitted to a user terminal via a Web server, and the cache control unit is requested to additionally register response data in a cache memory area.
[0012]
According to the present invention, registration in the cache area is sequentially registered when there is an inquiry request, and response data that needs to be updated and deleted is also registered at the next inquiry request. The waste of refreshing all of the inquiry requests can be eliminated.
[0013]
Further, the cache management means constantly monitors the update event table, and when an update event occurs, judges the content of response data corresponding to the update of the database, and notifies the cache control means of deletion. It is characterized by comprising monitoring means, and cache correspondence information management means for managing correspondence information between the contents of the database and the response data contents in the cache memory area.
[0014]
According to the present invention, it is possible to delete response data in the cache area to be refreshed in real time in response to the occurrence of an update event of the inquiry response database. Therefore, the data in the cache area can be only the contents synchronized with the database. Further, by providing a correspondence table between the database and the response data, a plurality of types of response data accompanying the database update can be deleted as refresh targets.
[0015]
The cache control means includes a cache area initialization means for securing and initializing a cache memory area when the server computer is started, and a recording time and a record search count (hit ratio) for each response data recording in the cache memory area. A cache area management means for managing and deleting a response data record having a low priority when a shortage occurs in an area; and searching for a corresponding cache memory area in response to a deletion notification from the cache management means, and searching for a corresponding response data. And a cache addition registering means for receiving new response data from the inquiry request response means and additionally registering the new response data in the cache memory area.
[0016]
According to the present invention, it is possible to store response data with a large number of inquiry requests in a limited cache area and exhibit a caching effect of reducing the number of times of accessing the database. Also, parallel processing and background processing can be performed with the inquiry request response means and the cache management means.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
FIG. 1 is a schematic diagram showing a configuration of a server computer device 100 with a cache memory control function according to the present invention.
[0019]
In the figure, reference numeral 1 denotes a user terminal for making an information inquiry request via the Internet. Reference numeral 6 denotes a system for providing real-time information to the server computer of the present invention. In this schematic diagram, the real-time information is received from the external real-time information providing system 6 via the communication control device 12 and recorded in the inquiry response database, and the cache memory control responding to the inquiry request from the user terminal 1 is performed. An embodiment will be described as a server computer 100 with a function.
[0020]
The server computer 100 with a cache memory control function performs a Web server 11 including a firewall connected to the Internet, a communication control device 12 connected to the real-time information providing system 6, and a business process for responding to an inquiry request. It comprises an application server 20 and a database 30 for recording inquiry response data.
[0021]
The database 30 includes at least a database update event table 32 that records update information of database contents in addition to a query response database 31, and a cache correspondence information table 33 that records correspondence information between database contents and cache memory contents. .
[0022]
The database update event table 32 is a table that records the data identification number and the update time stamp when the contents of the inquiry response database are updated, and is a record for transmitting an update event to the cache management unit. This table is a temporary recording table from which data processed by the cache management means is deleted. FIG. 1 shows a form in which the data is recorded in the database 30, but may be provided on a memory.
[0023]
The cache correspondence information table 33 is a table in which the correspondence between the data identification number of the inquiry response database and the identification number of the response data in response to the inquiry request from the user terminal is recorded. From this table, it is possible to determine the identification number of the response data to be refreshed with the update of the database.
[0024]
Next, a configuration of the application server 20 and a control function will be described. In this embodiment, the application server is an independent application server, but may be a central processing unit of a server computer.
[0025]
The application server 20 includes an inquiry request responding unit 21 that responds to an inquiry request from a user terminal, a database updating unit 22 that updates and records a database with the received real-time information and records the database in a database update event table 32, And a cache memory area 25 for recording the generated response data at high speed and capable of directly reading and writing, and a cache management means 23 for monitoring the update of the database and instructing the deletion of the corresponding response data in the cache memory contents. And cache control means 24 for registering / deleting a cache memory.
[0026]
By these means, the response data information synchronized with the contents of the database is always recorded in the cache memory area 25. In the cache memory area 25, response data classified by the identification number of the inquiry request is recorded. Since the data amount of the response data varies depending on the type of the inquiry request, the recording of the memory is dynamically managed by a known means.
[0027]
When receiving the inquiry request from the user, the inquiry request response means 21 first searches whether the corresponding response data is recorded in the cache memory area 25, and if not, searches the inquiry response database 31 to respond. Data is generated and transmitted to the user terminal 1 via the Web server 11, and the cache control means 24 is requested to additionally register response data in the cache memory area 25. According to this procedure, when response data is recorded in the cache area, a response is made at a high speed without accessing the disk of the database.
[0028]
If there is no response data in the cache area, this is the first query after startup, or when the database is updated and the cache area needs to be refreshed, or when the cache area is full and the priority is low, This is the case when it is deleted from the cache.
[0029]
The response data generated by reading the inquiry response database 31 is registered in the cache area, and is used in subsequent inquiry responses as information synchronized with the latest database until the database is updated.
[0030]
The database updating unit 22 is a unit that receives real information from the real-time information providing system 6 received via the communication control device 12 and records the real information in the inquiry response database 31. In the database update event table 32, a data identification number indicating an update content of the database and an update time stamp are recorded.
[0031]
The cache management means constantly monitors the update event table 32, and when an update event occurs, determines the content of response data corresponding to the update of the database, and notifies the cache control means 24 of the deletion. It comprises a monitoring means 23a and a cache correspondence information management means 23b for managing correspondence information between the contents of the database and the contents of the response data in the cache memory area.
[0032]
The database update event monitoring means 23a constantly monitors the database update event table 32, and when detecting an updated data identification number, deletes the response data identification number in the cache area corresponding to the data identification number. Notify the cache control means. At this time, the response data identification number corresponding to the data identification number is determined with reference to the cache correspondence information table 33. Note that the contents of the cache correspondence information table 33 can be read out from the disk at the time of startup and operated as a table on a memory that can be accessed at high speed.
[0033]
The cache correspondence information management unit 23b is a unit that performs a registration / change process of the cache correspondence information table 33 which is referred to by the database update event monitoring unit 23a for a deletion instruction determination for refreshing response data in a cache area.
[0034]
The cache control unit 24 includes a cache area initialization unit 24a, a cache area management unit 24b, a cache deletion unit 24c, and a cache addition registration unit 24d.
[0035]
The cache area initialization means 24a is means for securing and initializing a cache memory area when the server computer is started.
[0036]
The cache area management means 24b manages the recording time and the number of record searches (hit ratio) for each response data record in the cache memory area, and deletes a response data record with a low priority when the area becomes insufficient. It is. The low-priority data is data having a low hit rate used for an inquiry response after being recorded. By this means, a limited cache memory area is effectively used.
[0037]
The cache deletion unit 24c is a unit that searches the cache memory area and deletes the corresponding response data in response to the deletion notification of the response data identification number from the cache management unit. According to this means, instead of refreshing the cache area every time the conventional database is updated, the cache area is first deleted in real time, so that only response data synchronized with the database is recorded in the cache area, The query request response unit 21 can eliminate a useless process of performing a cache area synchronization confirmation process each time a user responds to an access.
[0038]
The cache additional registration unit 24d is a unit that receives new response data from the inquiry request response unit and additionally registers the new response data in the cache memory area.
[0039]
The operation of this means is to delete the response data (first time cache registration) created when responding to the first inquiry request after the start-up, and delete it from the cache by the cache deletion means 24c with updating of the database, or delete it because the cache area is full. In response to the inquiry request from the user, the inquiry request response means reads the latest inquiry response database 31 and generates the response data (refresh re-registration).
[0040]
In any case, the operation trigger is activated when there is an inquiry request access from the user. Therefore, it is possible to eliminate a useless process of refreshing a plurality of types of inquiry responses in advance.
[0041]
Next, an operation flow of the server computer with a cache memory control function of the present invention will be described with reference to FIG. The numbers attached to the arrows indicate the processing steps.
[0042]
(1) is a step of allocating and initializing the cache area 25 when the server is started, which is performed by the cache area initializing means 24a.
[0043]
(2) is a step in which, in response to the inquiry request from the user A, the inquiry request response means 21 first searches the cache area, and if there is response data, reads from the cache area and responds.
[0044]
Step (3) is a step of accessing the inquiry response database 31 to read and respond to data if there is no response data in the cache area in step (2).
[0045]
The step (4) is a step of passing the response data generated in the step (3) to the cache additional registering means 24d and registering it in the cache area 25.
[0046]
Steps {circle around (2)} to {circle around (4)} are repeated, and response data having an inquiry response is accumulated in the cache area 25.
[0047]
(5) The cache area management means 24b records the recording time of the response data recorded in the cache area 25 and the number of inquiries, and when the accumulated response data becomes full, the number of inquired requests (hit ratio) This is a step of deleting the information having less number and securing a free area that can be recorded in the area.
[0048]
In parallel with the business processes of (2) to (5), the database updating means 22 repeats the step (6) of updating the inquiry response database every time the B real information is received.
[0049]
In the step (7), the step of recording the updated database identification number in the database update event table 32 is repeated at the same time as the step (6).
[0050]
(8) a step in which the database update event monitoring means 23a constantly monitors the database update event table 32, determines the identification number of the associated response data every time an update event occurs, and notifies the cache deletion means 24c of the deletion. It is.
[0051]
Step (9) is a step in which the cache deletion unit 24c, which has received the deletion notification from the step (8), immediately deletes the response data of the identification number corresponding to the cache area 25, if any.
[0052]
The operations (2) to (5), the operations (6) to (7), and the operations (8) to (9) operate in parallel.
[0053]
【The invention's effect】
The server computer device with a cache memory control function of the present invention has the following effects.
[0054]
That is, response data in which synchronization of the cache area is guaranteed can be obtained. Further, it is possible to eliminate the disk access operation for the synchronization check using the time stamp of the cache memory and the database.
[0055]
Further, it is possible to eliminate waste of refreshing all of various types of inquiry requests. Further, the data in the cache area can be only the contents synchronized with the database. Further, a caching effect of reducing the number of times of accessing the database can be exhibited.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a configuration of a server computer device with a cache memory control function of the present invention.
FIG. 2 is an explanatory diagram illustrating an operation flow of a server computer with a cache memory control function according to the present invention.
[Explanation of symbols]
1 User terminal 5 Internet 6 Real-time information providing system 11 Web server 12 including firewall 12 Communication control device 20 Application server (central processing unit)
21 inquiry request response means 22 database update means 23 cache management means 23a database update event monitoring means 23b cache correspondence information management means 24 cache control means 24a cache area initialization means 24b cache area management means 24c cache deletion means 24d cache addition registration means 25 Cache memory area 30 Database 31 Query response database 32 Database update event table 33 Cache correspondence information table

Claims (4)

A server computer that has a database that is updated in real time as needed, receives an inquiry request from a user terminal via the Internet, and returns response information obtained by searching and processing the request content selected by the user from the database. So,
The server computer device includes a Web server that receives an inquiry request from a user, a database server that records real-time information received from a real-time information providing system via a communication control device, and an information inquiry request from a user terminal. And an application server that responds by searching, reading and processing the database of the database server, and transmitting the processed data via the Web server.
The database server includes at least a database update event table that records update information of database contents in addition to the inquiry response database, and a cache correspondence information table that records correspondence information between database contents and cache memory contents.
The application server includes: an inquiry request response unit that responds to an inquiry request from a user terminal; a database updating unit that updates and records a database with the received real-time information and records the database in a database update event table; A high-speed, directly readable / writable cache memory area for recording created response data, a cache management means for monitoring the update of the database and instructing deletion of the corresponding response data in the cache memory contents, and registration of the cache memory A server computer device with a cache memory control function, comprising: cache control means for performing deletion; and response data information synchronized with the contents of the database is always recorded in the cache memory area. The inquiry request response means, upon receiving an inquiry request from a user, first searches whether the corresponding response data is recorded in the cache memory area, and if not, searches the inquiry response database to generate response data. 2. The server with a cache memory control function according to claim 1, further comprising: transmitting the response data to a user terminal via a Web server; and requesting the cache control means to additionally register response data in a cache memory area. Computer device. The cache management means constantly monitors the update event table, and when an update event occurs, determines the content of response data corresponding to the update of the database, and notifies the cache control means of deletion. 2. The server computer device with a cache memory control function according to claim 1, further comprising: a cache correspondence information management unit that manages correspondence information between database contents and response data contents in the cache memory area. The cache control means secures and initializes a cache memory area when the server computer is started, and manages a recording time and a record search count (hit rate) for each response data record in the cache memory area. A cache area management unit for deleting a low-priority response data record when an area shortage occurs, and a search for a corresponding cache memory area in response to a deletion notification from the cache management means to delete a corresponding response data. 4. A cache memory control function according to claim 1, further comprising: a cache deletion unit for performing the above operation, and a cache addition registration unit that receives new response data from the inquiry request response unit and additionally registers the new response data in a cache memory area. Server computer device.

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